Motor vehicles with internal combustion engines have vehicle driver controls and brakes that function to regulate the vehicle's acceleration, deceleration and stopping. The driver controls have foot pedals, mechanical linkages and electronic systems that allow the driver to operate the motor vehicle. Malfunction of the driver controls can result in unexpected and sudden vehicle acceleration that the driver is unable to stop the vehicle using its brakes. Motor vehicle braking systems are not designed to brake against full engine power and will overheat and lose some, if not most, of their effectiveness. The motor vehicle is out of control of the driver during unexpected acceleration situations which can cause vehicle damage and personal injury.
Model A Ford motor vehicles have internal combustion engines equipped with carburetors having throttle valves that control the flow of air through the carburetors to the engines. When the throttle valves are fully open, the engines operate at full speed. Foot pedals connected with linkages to the throttle valves control the positions of the valves to regulate the flow of air into the carburetors and resulting speed of the engine. The linkages can dislodge from the throttle valves or become stuck thereby causing the throttle valves to move to wide open positions whereby the engines race at excess speeds. This results in an unintended acceleration of the motor vehicle. The ignition dash board switches must be turned off to stop the engines as the brakes on these motor vehicles are ineffective to stop the vehicle with the engines operating at full speed.
R. V. Albertson in U.S. Pat. Nos. 3,672,344 and 3,742,928 discloses internal combustion engines having manually operable throttle controls connected to carburetor gas flow control valves with linkages. Electric switches associated with the linkages ground the electrical ignition circuits of the engines when the linkages, such as throttle cables, stick in throttle open positions. When the ignition circuits are grounded, the engines cease to operate.
S. Yamashi in U.S. Pat. No. 4,955,255 discloses a control system for a motor vehicle that automatically cuts off the power of the engine when an abnormal condition in the power transmission system is detected. The vehicle has a brake switch for producing a brake signal when a brake pedal is depressed. A vacuum switch produces an acceleration signal when pressure in the air intake passage of the engine exceeds a predetermined value. An engine speed sensor produces an engine speed signal when the engine speed exceeds a predetermined speed. A transmission control responsive to the brake signal, acceleration signal and engine speed signal operates to shift the transmission to a neutral range.
Modern motor vehicles are controlled electronically to improve fuel economy, reduce pollution, improve driving safety and reduce manufacturing costs. The electronic controls are subjected to hot and cold temperatures, humidity, vibration, mechanical shock, electrical interference and corrosive pollutants that can cause the electronic controls to malfunction. Some of the malfunction controls may be benign whereas others can be dangerous and cause accidents and endanger human life.
Cruise control systems are used with motor vehicles to keep the vehicle's speed constant on long runs and help prevent driver fatigue. Software interlocks are included in cruise control systems to prevent the cruise control from operating in certain gears and below selected speeds. Safety switches deactivate the cruise control when the brakes are applied. The malfunction of the cruise control system of a motor vehicle can result in unintended sudden acceleration of the vehicle.
Electronic throttle controls were introduced in motor vehicles in 1988. With electronic throttle control, the driver no longer controls the throttle by means of linkages between the accelerator foot pedal and throttle. An electronic link from the foot pedal to the electronic throttle control works in conjunction with the electronic engine control unit to control the engine speed. The electronic systems are safely critical systems with potential to fail by causing the vehicle to suddenly accelerate.